There I was.... motorsailing across the shipping lane of hte Santa Barbara Channel, in the fog, when my trusty Yanmar 2GM20F started losing revs. From cruising at 2700 rpm, it would fall off to anywhere from 1500 to 2000 for a minute or so, then build back up. I should mention that we were beating into very small seas, 1 to 2 feet. Then, while the Commodore and I held our breaths, it just.......... slowly died........ and there we were (no radar, of course), 2 miles from a fog-shrouded island shore. OK, we made our way back, through the fog, avoided the ships (of which there were none), the wind died, we tried the engine again, it worked, the fog got to pea-soup quality, we couldn't see the first red bouy at the harbor till we were 100 feet away (it was the sea lions that guided us more than the buoy horn) but didn't fancy trying the harbor entrance in these conditions. Went back out to a mile off-shore, anchored and turned on ALL our lights *yks Kept watch, including shining our spotlight on the mast at the sound of any engine, then, at about 1am, the fog cleared and the entire shoreline was perfectly visible. By the time we got past the first red buoy, we could barely see the next, but we groped onward, finally finding our slip. There, whew, we're home. So the question (for anyone who made it this far) is: What is the likely cause of our engine dying? I won't make any guesses - that would spoil it, right? Cheers, Bob s/v X SAIL R 8
Engine woes
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Is this a Test?
Not sure if you are asking for the possible cause of loss of RPM's or asking if we can guess the cause ..... Ennyhoo, our Yanmar 1 cyl diesel went through the same throws of near-death .... after rebuilding the top-end of the motor we discovered that the cause was a carbon buildup in the exhaust. The opening had closed to less than 1/8 inch in diameter.
Not sure if you are asking for the possible cause of loss of RPM's or asking if we can guess the cause ..... Ennyhoo, our Yanmar 1 cyl diesel went through the same throws of near-death .... after rebuilding the top-end of the motor we discovered that the cause was a carbon buildup in the exhaust. The opening had closed to less than 1/8 inch in diameter.
Either water in the fuel, or out of fuel
When was the last time you cleaned out the water sep filter?
When was the last time you cleaned out the water sep filter?
Probable cause ......
...accumulated particulate adhering to the fuel tank walls breaking loose and 'slugging' the filters; plus, water in the bottom of the tank mixing with 'good fuel'. If the fuel is 'old' then the 'gums & varnishes' formed will not burn well in the combustion chambers and will 'coke' in the exhaust system causing a restriction. Answer: Unmaintained & Dirty Fuel tank.
...accumulated particulate adhering to the fuel tank walls breaking loose and 'slugging' the filters; plus, water in the bottom of the tank mixing with 'good fuel'. If the fuel is 'old' then the 'gums & varnishes' formed will not burn well in the combustion chambers and will 'coke' in the exhaust system causing a restriction. Answer: Unmaintained & Dirty Fuel tank.
Fuel Filter(s) Clogged?
Or your mixing elbow is clogged. But that wouldn't go away but it would allow you to start again. Check the filters.
Or your mixing elbow is clogged. But that wouldn't go away but it would allow you to start again. Check the filters.
Sounds like the mixing elbow to me
Some call it the exhaust riser. It is where the water is pumped into the exhaust stream to cool it down. That is what mine did. RPMs would drop, exhaust would get black, it would run ok at lower speed, engine would die and then I would restart. This got progressively worse until it would not start at all.
Some call it the exhaust riser. It is where the water is pumped into the exhaust stream to cool it down. That is what mine did. RPMs would drop, exhaust would get black, it would run ok at lower speed, engine would die and then I would restart. This got progressively worse until it would not start at all.
Not a test, Dave, just soliciting some advice.
I suspect the fuel filter and/or water separator, but wanted to see if there were more possibilities. My mixing elbow was represented by the PO as being 2 years old, so I'm hoping that isn't the problem. I have ordered a fuel filter element and will replace that and service the water separator this weekend (if the Long Beach boat show leaves us time..... gotta go do some dreaming
I use a water-treatment for my fuel tank, but have read here that the biocides should be avoided. I'm not sure what to do about 'old' fuel.... it's an 18 gallon tank and I haven't used more than 15 gallons (at .3 gal/hr) in the 5 months I've owned the boat. I do top it off when it's down a few gallons. Thanks for all the advice and suggestions. Cheers, Bob s/v X SAIL R 8
I suspect the fuel filter and/or water separator, but wanted to see if there were more possibilities. My mixing elbow was represented by the PO as being 2 years old, so I'm hoping that isn't the problem. I have ordered a fuel filter element and will replace that and service the water separator this weekend (if the Long Beach boat show leaves us time..... gotta go do some dreaming
I use a water-treatment for my fuel tank, but have read here that the biocides should be avoided. I'm not sure what to do about 'old' fuel.... it's an 18 gallon tank and I haven't used more than 15 gallons (at .3 gal/hr) in the 5 months I've owned the boat. I do top it off when it's down a few gallons. Thanks for all the advice and suggestions. Cheers, Bob s/v X SAIL R 8Ours was algae growth
Same thing happened to us, crossing Lake Erie, had to get a tow. WE thought we had air in the lines, or water in our fuel, turns out our boat (which we had just shipped from SC) had algae growing in the tank, that had clogged the fuel filter and was starving the engine. Not sure if you have checked this option, but thought I would share the possibility. We are still struggling with what to do, we keep the tank above half full and it seems to not pull the algae through, and we installed an algae x system. We were warned not to use any biocides; will fill MANY filters in a row with dead algae.
Same thing happened to us, crossing Lake Erie, had to get a tow. WE thought we had air in the lines, or water in our fuel, turns out our boat (which we had just shipped from SC) had algae growing in the tank, that had clogged the fuel filter and was starving the engine. Not sure if you have checked this option, but thought I would share the possibility. We are still struggling with what to do, we keep the tank above half full and it seems to not pull the algae through, and we installed an algae x system. We were warned not to use any biocides; will fill MANY filters in a row with dead algae.
Fuel Filter
Sure sounds like fuel filters to me. That is exactly the way I'd expect the engine to act. Beating into a chop stirs up the gunk in the tank which fouls the filters. All good suggestions above but I wouldn't look any farther before doing the simplest most logical thing... change the filters.
Sure sounds like fuel filters to me. That is exactly the way I'd expect the engine to act. Beating into a chop stirs up the gunk in the tank which fouls the filters. All good suggestions above but I wouldn't look any farther before doing the simplest most logical thing... change the filters.
Filters are not the problem .....
Filters will only remove whats available in the system to be removed. If you've never cleaned out the tank, have thick particulate sticking onto the tank walls, degraded/decomposed fuel, have a goodly amount of biomass growing at the water/oil interface .... filters will NEVER remedy such a problem. Such filters only have a few 'grams' (25-50g) of crud capacity. If your filters are failing, it means that you forgot to maintain the tank.
Filters will only remove whats available in the system to be removed. If you've never cleaned out the tank, have thick particulate sticking onto the tank walls, degraded/decomposed fuel, have a goodly amount of biomass growing at the water/oil interface .... filters will NEVER remedy such a problem. Such filters only have a few 'grams' (25-50g) of crud capacity. If your filters are failing, it means that you forgot to maintain the tank.
i beg to differ
Only if the filters are plugging repeatedly in a short time span. But normally a good dual filtration system such as a Raco should easily be able to handle a little crap in the tank. Unless it's a real mess in there a couple of filter changes over one or 2 tanks of fuel should handle it. If not, have the fuel polished and the tank cleaned. But start with the most basic solutio before going off onto all the other stuff!
Only if the filters are plugging repeatedly in a short time span. But normally a good dual filtration system such as a Raco should easily be able to handle a little crap in the tank. Unless it's a real mess in there a couple of filter changes over one or 2 tanks of fuel should handle it. If not, have the fuel polished and the tank cleaned. But start with the most basic solutio before going off onto all the other stuff!
Check The Racor
Bob, Exact same thing has happened to me twice in past three years. Each time it was algea in the tank. I was getting moisture (water)through a bad gasket "O" ring on the fuel filler cap. If you check the fuel filter in the Racor or other fuel filter and if it is black then there is your problem. Easy check and no cost. If that is your problem then the tank should come out and be steamed out to get rid of it. Adding Bio clean at this point only kills it and it stays in the tank on the bottom and plugs you up again. After the last encounter on May 21st. I now have an extra lenght of fuel line hose which I can stick into one of the two 1 gallon gerry cans of diesel I have on board. I can then bypass the filter and get myself home or somewhere safe.
Bob, Exact same thing has happened to me twice in past three years. Each time it was algea in the tank. I was getting moisture (water)through a bad gasket "O" ring on the fuel filler cap. If you check the fuel filter in the Racor or other fuel filter and if it is black then there is your problem. Easy check and no cost. If that is your problem then the tank should come out and be steamed out to get rid of it. Adding Bio clean at this point only kills it and it stays in the tank on the bottom and plugs you up again. After the last encounter on May 21st. I now have an extra lenght of fuel line hose which I can stick into one of the two 1 gallon gerry cans of diesel I have on board. I can then bypass the filter and get myself home or somewhere safe.
Thanks, everybody
I'm going to start with the fuel filters. That will give me some input. If they are gunked up, I'll know to look towards the fuel tank. If not, then it's on to the mixing elbow. RichH, it isn't that I forgot to maintain the fuel tank, it's a matter of available time and priorities. Jim, can you explain 'have the fuel polished'? Cliff, I like your emergency backup... I have a 1-gal plastic fuel jug, so I reckon I'll invest in a length of fuel hose. (Of course that won't help with a mixing elbow problem). I'll post the results Monday if I get a chance to get to the boat this weekend. Stay tuned! Cheers, Bob s/v X SAIL R 8
I'm going to start with the fuel filters. That will give me some input. If they are gunked up, I'll know to look towards the fuel tank. If not, then it's on to the mixing elbow. RichH, it isn't that I forgot to maintain the fuel tank, it's a matter of available time and priorities.
Jim, can you explain 'have the fuel polished'? Cliff, I like your emergency backup... I have a 1-gal plastic fuel jug, so I reckon I'll invest in a length of fuel hose. (Of course that won't help with a mixing elbow problem). I'll post the results Monday if I get a chance to get to the boat this weekend. Stay tuned! Cheers, Bob s/v X SAIL R 8or, have the fuel "scrubbed"
Crud (and probably water) in the tank seems the likely culprit, but there are several ways to take that on. - Keep a lot of filters on hand and change them frequently(the irritating fix); -- Pay a yard to pull the tank and steam clean it (an expensive solution) or replace it; -- Pay a fuel scrubbing service to clean your diesel fuel. They provide the equipment and the elbow grease, but it can be pricey. IF you go this route, get a 90 day warranty on the work so if they do a poor job (I had it done once) they'll come back and do it again; -- Build your own fuel scrubber (small pump and a good Racor filter) and do it yourself, preferably once a year. Once you get it cleaned up, make a point to keep you tank topped off to prevent moisture vapors condensation which provides a place for gunk to grow,., That suggestion will bring up a debate from the folks who believe other approaches are better, but that's what makes this forum fun. Sanders
Crud (and probably water) in the tank seems the likely culprit, but there are several ways to take that on. - Keep a lot of filters on hand and change them frequently(the irritating fix); -- Pay a yard to pull the tank and steam clean it (an expensive solution) or replace it; -- Pay a fuel scrubbing service to clean your diesel fuel. They provide the equipment and the elbow grease, but it can be pricey. IF you go this route, get a 90 day warranty on the work so if they do a poor job (I had it done once) they'll come back and do it again; -- Build your own fuel scrubber (small pump and a good Racor filter) and do it yourself, preferably once a year. Once you get it cleaned up, make a point to keep you tank topped off to prevent moisture vapors condensation which provides a place for gunk to grow,., That suggestion will bring up a debate from the folks who believe other approaches are better, but that's what makes this forum fun. Sanders
fuel polishing
Like Sanders said only he called it Scrubbed. Most pro companies advertise it as fuel polishing. Check the regional magazines for ads. They use a high pressure recirculating jet of fuel to blast the crud off the tank walls while simultainiously filtering the fuel at a high rate. Chances are the filters just haven't been changed in a long time and all the motion stirred up some crud. After all that is what they are there for. So it just makes the most sense to do what you said and change them. If that's not the problem at least you eliminated the most obvious and least expensive thing first.
Like Sanders said only he called it Scrubbed. Most pro companies advertise it as fuel polishing. Check the regional magazines for ads. They use a high pressure recirculating jet of fuel to blast the crud off the tank walls while simultainiously filtering the fuel at a high rate. Chances are the filters just haven't been changed in a long time and all the motion stirred up some crud. After all that is what they are there for. So it just makes the most sense to do what you said and change them. If that's not the problem at least you eliminated the most obvious and least expensive thing first.
Backup Jerry Can
A note on the jerry can idea: Remember that even if your engine only uses 1/3 gallon an hour, the fuel pump will pull much more than that out of the jerry can and return it to your boat's tank. One gallon won't last very long.
A note on the jerry can idea: Remember that even if your engine only uses 1/3 gallon an hour, the fuel pump will pull much more than that out of the jerry can and return it to your boat's tank. One gallon won't last very long.
fuel woes
Bob; I had the same problem in Mexico a few years ago. If none of the previous suggestions work, check the lift pump. The check valve in mine was shot. A Mexican mechanic cannabalized one together out of mine and another one. The fine-mesh screen in there might be clogged, too. Also, check your fuel pick-up tube in the tank. If there's a screen on the bottom of the tube, cut it off and throw it away.
Bob; I had the same problem in Mexico a few years ago. If none of the previous suggestions work, check the lift pump. The check valve in mine was shot. A Mexican mechanic cannabalized one together out of mine and another one. The fine-mesh screen in there might be clogged, too. Also, check your fuel pick-up tube in the tank. If there's a screen on the bottom of the tube, cut it off and throw it away.
Weekend update
I drained the first filter (a Racor 230 series) and found some, but not a lot of black gunk and some water. Then I went to the engine filter, replaced the element and cleaned the bowl. Again it was not what I would call very dirty. I didn't find any detailed bleeding instruction in the Yanmar manual, so I cranked the starter with the bleed bolt loose until the engine caught (no fuel came out of the bolt - I don't know if there should have been some) and ran it for about 20 minutes at increasing RPM. It 'sagged' a little in the first minute, but ran fine after that. Can anybody enlighten me as to the proper method of bleeding the fuel line? Thanks. So I'm going to order and install a new (10 micron) element for the Racor. I'll also put a second, parallel Racor and plumbing on my list, but not high priority. I didn't see any accumulation of crud on the walls of the fuel tank. That's also on my list for replacement - very low priority - because I want a fuel gauge, which Hunter obviously didn't find necessary. (They didn't even put a fitting in the top of the tank that could hold a sensor). So thanks to all the valuable advice. Cheers, Bob s/v X SAIL R 8
I drained the first filter (a Racor 230 series) and found some, but not a lot of black gunk and some water. Then I went to the engine filter, replaced the element and cleaned the bowl. Again it was not what I would call very dirty. I didn't find any detailed bleeding instruction in the Yanmar manual, so I cranked the starter with the bleed bolt loose until the engine caught (no fuel came out of the bolt - I don't know if there should have been some) and ran it for about 20 minutes at increasing RPM. It 'sagged' a little in the first minute, but ran fine after that. Can anybody enlighten me as to the proper method of bleeding the fuel line? Thanks. So I'm going to order and install a new (10 micron) element for the Racor. I'll also put a second, parallel Racor and plumbing on my list, but not high priority. I didn't see any accumulation of crud on the walls of the fuel tank. That's also on my list for replacement - very low priority - because I want a fuel gauge, which Hunter obviously didn't find necessary. (They didn't even put a fitting in the top of the tank that could hold a sensor). So thanks to all the valuable advice. Cheers, Bob s/v X SAIL R 8
On top of the Racor mount is a nylon knob,
unscrew it and it pops up and becomes a plunger to prime the line and filter. The bleed screw must be open for the air to have somewhere to escape. My Perkins has 2 bleed screws, 1 at start of fuel line on engine and one at the end. I open first bleed point, (actually a Banjo fitting on the line) prime with the pump on the Racor filter till I get fuel to the bleeder, close that bleed point, open second and prime rest of line with a lever on the engine which is a second pump. Not sure if your engine has this second priming pump but you should be able to get most of the air out with the pump on the filter mount.
unscrew it and it pops up and becomes a plunger to prime the line and filter. The bleed screw must be open for the air to have somewhere to escape. My Perkins has 2 bleed screws, 1 at start of fuel line on engine and one at the end. I open first bleed point, (actually a Banjo fitting on the line) prime with the pump on the Racor filter till I get fuel to the bleeder, close that bleed point, open second and prime rest of line with a lever on the engine which is a second pump. Not sure if your engine has this second priming pump but you should be able to get most of the air out with the pump on the filter mount.
Thanks, Ted
That sounds pretty simple. I haven't seen any mention of a second bleed pump on the engine (Yanmar 2GM20F) but I will look again at the manual. Guess I should bring the Commodore or other helper along when bleeding from the Racor - it is installed in the starboard cockpit locker. I can barely fit in the locker and can't possibly see the engine from there! Cheers, Bob s/v X SAIL R 8
That sounds pretty simple. I haven't seen any mention of a second bleed pump on the engine (Yanmar 2GM20F) but I will look again at the manual. Guess I should bring the Commodore or other helper along when bleeding from the Racor - it is installed in the starboard cockpit locker. I can barely fit in the locker and can't possibly see the engine from there! Cheers, Bob s/v X SAIL R 8
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